Vehicles, such as construction and forestry equipment, typically enclose an engine, cooling system and other vehicle components. Such vehicles commonly utilize liquid cooled internal combustion engines which generate heat during their operation. Liquid-cooled engines employ pressurized coolant circulated through the engine to absorb heat. The heated coolant is subsequently passed through a heat exchanger such as a radiator to dissipate heat from the coolant to the atmosphere, after which the coolant is recirculated to the engine for further engine cooling. As the coolant is passed through the heat exchanger, air flows through the heat exchanger to absorb heat and carry it out into the atmosphere. Air is commonly drawn or propelled through the radiator and/or oil cooler by use of a fan. Vehicles also may include a baffle to prevent the air supply from being heated by the engine as the air is drawn to and passed through the radiator and/or oil cooler.
The capacity of a cooling system in such a vehicle depends on many factors including the velocity and volume of air flowing through the heat exchanger, as well as the distribution of the air flow over the available heat exchange surface of the radiator and/or oil cooler. These vehicles may be used in construction, forestry or other dirty environments with high levels of airborne particulate matter, so the air used to cool the radiator is frequently contaminated with dust, dirt and similar debris. Typically, such vehicles will include grilles or screens over their air intakes to reduce debris present in the cooling air while allowing the air to pass into the area enclosed by the hood to cool the engine by interaction with the radiator and/or oil cooler. However, debris may accumulate on and around the outer surface of the grille or screen, clogging the intake and restricting the air flow. In these vehicles, debris tends to build up rapidly and accumulate first on those areas of a grille or screen where air flows at the highest velocity. Air velocity at some areas of a grille or screen may be substantially higher than the velocity at other areas. Areas of the grille or screen that are relatively close to the air inlet side of the radiator and/or oil cooler may have air flow velocities several times higher than areas further away from the air inlet side of the radiator and/or oil cooler. For example, the air velocity may be as high as 20,000 mm/second at air intake openings near the air inlet side of the radiator and/or oil cooler, and less than 1000 mm/second at air intake openings furthest from the radiator. Areas of the grille or screen that provide air flow to relatively larger areas of the radiator and/or oil cooler may also have air flow velocities several times higher than areas that provide air flow to relatively smaller areas of the radiator and/or oil cooler. For example, the air velocity may be as high as 20,000 mm/second at air intake openings servicing larger sections of the radiator and/or oil cooler, and less than 1000 mm/second at air intake openings servicing smaller sections of the radiator and/or oil cooler.
If enough debris accumulates to block the portion of the grille or screen with the highest air velocity, the effective air intake area is reduced. As a result, the vehicle's engine may not be cooled as efficiently or quietly.
A baffle structure is needed for such a vehicle that provides improved air flow efficiency. A baffle structure is needed that can provide a supply of cooling air to an engine for a construction or forestry vehicle or similar vehicle without the flow being interrupted or compromised due to blockages of the grille or screen caused by dust, dirt or similar debris. A baffle structure on a construction or forestry vehicle or similar vehicle is needed that can provide more uniform and even air flow velocity across different areas of a grille or screen. A baffle structure for a construction or forestry vehicle or similar vehicle is needed that includes an air intake that provides more uniform air flow while minimizing engine noise escaping from the engine compartment.